An airline kennel needs to be ventilated on all four sides, usually (some airlines say three), needs Live Animal stickers, and needs the special cups that lock on the inside of the door. It also has to be able to be picked up from the outside, no need to put fingers inside any grating. So I am not sure the Wal-Mart crates will work.
The problem with waiting until four weeks to worm is that if the puppies have worms now (and if their mom did, they do--the worms actually migrate through the placenta and directly into the puppies, so they're born with them) by four weeks they'll have a serious load and be fighting to stay healthy. Pyrantel is VERY safe; every breeder I know uses it on the 2/4/6/8 (meaning weeks old) schedule. Right now, at two weeks, they've got fifth-stage larvae in them; in another week the worms will be egg-laying adults. So you hit them now and every two weeks, so any larvae is killed and doesn't have a chance to mature to a big worm and re-infest everybody.
From Pfizer (which makes Nemex, one of the brand-name pyrantel wormers):
"For maximum control and prevention of reinfestation, it is recommended that puppies be treated at 2, 3, 4, 6, 8, and 10 weeks of age. Lactating bitches should be treated 2–3 weeks after whelping."
I don't do the three-week worming; I understand the thought behind it (it's to kill anything that was left behind by the 2 week one) but I have had clear fecals for all my litters doing the worming at 2-week intervals.